Position a rack in the lower third of the oven and preheat to 350 degrees. Grease and flour two 9-by-2-inch round cake pans.

Sift the flour, baking powder and salt onto a piece of wax paper or into a bowl; set aside.

In the bowl of a heavy-duty mixer fitted with the paddle blade, beat the butter on medium speed 45 seconds until it is light in color. Add the sugar in a steady stream, then stop the machine and scrape down the side of the bowl. Resume beating, stop occasionally to scrape down the side of the bowl, and beat 4 to 5 minutes until the mixture is very light in color and texture.

Change to the whip attachment and gradually pour in the eggs, about a tablespoon at a time. (If the mixture looks curdled, stop adding the eggs, increase the speed to high, and beat until it looks smooth and shiny. Return the speed to medium, and add the remaining eggs.) Continue beating until the mixture is ivory colored. The entire process of adding and beating the eggs should take 3 to 4 minutes.

Reduce the mixer speed to low. Add the flour mixture in four additions, alternating with three additions of the milk. After each addition, beat until smooth and scrape down the side of the bowl. Beat in the vanilla with the final addition of milk. Divide the batter evenly between the prepared pans and spread evenly.

Bake about 30 minutes until the tops spring back when the cakes are lightly pressed in the centers and a toothpick inserted in the centers comes out clean.

Transfer the layers to wire cooling racks and cool 10 minutes. Invert onto the racks or plates and remove the pans. Cool completely before wrapping or decorating. Any warmth will melt icing or create moisture if wrapped.

Place one layer, flat side up, on work surface. Ice top surface with buttercream. Place second layer, flat side down, on top. Ice top and side of cake with a very thin layer of buttercream. You are now ready to decorate the cake with fondant. Makes 8 servings.